Analysis of the Ultimate Intrinsic Signal-To-Noise Ratio (“UISNR”) through a current mode expansion employing dyadic Green's functions (“DGF”) (See, e.g., 1 and 2) can make it possible to plot the current pattern on a given surface which can result in the UISNR for a given position in the phantom, which can be called the ideal current pattern (See, e.g., References 1 and 3). For a cylindrical phantom with a concentric cylindrical surface, the ideal current pattern which maximizes central signal to-noise ratio (“SNR”) can look like a pair of distributed loops at low field (See, e.g., FIG. 1, section 110). At high fields, however, the ideal current pattern for central SNR can assume a pattern that can be a mixture of loops and electric dipole components (See, e.g., Reference 3).
A contribution of the latter to UISNR can increase with frequency (See, e.g., References 3 and 4) and, for certain geometries, the ideal current pattern can be dominated by electric dipole currents, in which the current can flow in straight lines along the length of the cylinder with no return path (See, e.g., FIG. 1, section 120). Traditionally, a common antenna structure for magnetic resonance imaging (“MRI”) can be a surface coil loop. Although conventional stripline coils or transverse electro-magnetic (“TEM”) elements can appear to mimic an electric dipole antenna, both can rely on the presence of a closely coupled shield, which can provide a return path, and therefore can support loops of current rather than electric dipole currents.
Thus, there may be a need to address and/or overcome at least some of the above-described deficiencies.